Telephone system



May 5, 1936.

J C. KELLY TELEPHONE SYSTEM Filed Jan. 23, 1935 2 Sheets-Sheet l lNl/ENTOR 4 J. c, KELLY A T TORNEY y 1936. J. c. KELLY 7 2,039,650

TELEPHONE SYSTEM Filed Jan. 25, 1955 2 Sheets-Sheet 2 l I HP F IH lq 0 w9 $1 9 z M Q- l IIHII INVEN TOR J. C. KELLY A 7 ORNEY Patented May 5,1936 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM York ApplicationJanuary 23, 1935, Serial No. 2,986

10 Claims.

This invention relates to telephone systems and particularly to remotecontrol systems in which the establishing of connections betweensubscribers lines at a branch exchange is controlled by an operator at amain exchange.

It is an object of this invention to simplify the equipment used at thebranch exchange for systems of this kind to respond to control over atrunk line from the main exchange.

Heretofore systems of this kind have been used in which, in response toa calling subscriber in a branch exchange removing his receiver from theswitchhook, a line switch is operated to connect an idle trunk from amain exchange to the calling subscribers line and to signal an operatorat the main exchange that a connection is desired. After having answeredthe call and received the called subscribers number the operator thendials the number back over the trunk and causes a selector switchassociated with the trunk and the line switch to extend the connectionbetween the calling line and the called line over these switches.

It is a feature of this invention to provide a single trunk line betweena branch exchange and a main exchange and a single switch at the branchexchange for the purpose of controlling the establishing of connectionsbetween subscribers lines at the branch exchange and from subscriberslines at the branch exchange to subscribers lines at the main exchangeby the aid of an operator at the main exchange.

Another feature of the invention is to employ the switch to connect acalling line in the branch exchange to the trunk and to employ theswitch to connect the trunk to a called line in the branch exchange.

Another feature of the invention is to provide means whereby when a callis made to an operator at the main exchange the connection from thecalling line to the trunk extends through contacts of the switch andwhereby when a call is made to another subscribers line in the branchexchange the connection between the calling sub- 45 scribers line andthe trunk is exchanged to extend directly from the calling line to thetrunk independent of the switch, and the connection from the trunk tothe called subscribers line extends through contacts of the switch.

5 It is another feature of the invention to provide means whereby theconnection of a calling subscribers line to the trunk is effected inresponse to ringing current received over the call- I ing line from thecalling subscribers ringing current generator.

It is another feature of the invention to provide means operative if thetrunk is in use and a connection is desired by another subscriber at thebranch exchange to signal the operator at the main exchange by aflashing signal and to signal 5" the connected calling subscriber andcalled subscriber and the operator by an audible signal.

The invention is illustrated in the accompanying drawings in which:

Fig. 1 shows the equipment at a branch ex- 10- change with astep-by-step switchused for controlling the establishing of connectionsbetween subscribers lines at the branch exchange and for subscriberslines at main exchange; while,

Fig. 2 shows a trunk circuit leading to main exchange and an operatorsposition.

The establishing of a connection from one calling subscriber at thebranch exchange to another calling subscriber at the same exchange willnow be described. When the subscriber at l wants to establish aconnection he first operates his hand generator which causes current tobe transmitted over the tip and ring conductors through the upperwinding of relay 2 and the upper inner armature and back contact. 2 tooperate partially to open and close connections at armatures marked X.Thus this circuit through the upper Winding of relay 2 is opened while aholding circuit for relay 2 is closed from battery, third and secondlower armatures of this relay through the lower winding to ground. Aground is removed from the marking contact corresponding to the callingline on bank B of switch SS, and a circuit is closed to operate the,relay 3 from battery through the upper winding of this. relay, contactsof relay 4, second upper armature and front contact of relay 2, toground at the third upper armature and back contact of this relay.Normally relay 5 is operated over a circuit from battery through thewinding of this. relay through back contacts of relay 3 over the tip andring conductors of the trunk through the wind ngs of a normally operatedrelay IIJO to the charging battery [0| over contacts of this relay andrelay I02. Relays 5 and I0!) are now released due to the operation ofrelay 3. The release of relay 5 performs no function at this time. RelayI!!!) in releasing closes a circuit for lamp I03 from battery contactsof jack I04, contacts of relays I00 and I02 through lamp I03 to. ground.

When now the operator at the main offlce answers by inserting a plug I05of an answering cord into jack I06, relay I02 operates from bat- 55:

tery through the winding of this relay, contacts This causes relay 25 ofthe jack I06 to ground. This removes the windings of relay I00 from thering conductor and connects battery to the tip and ring conductors forthe completion of two circuits, one for relay 7 from battery, contactsof jack I04, lower winding of relay IIO, contacts of relay I 02, tipconductor, contacts of relay 3, a winding of repeating coil 6, windingof relay I to ground at contacts of relay 3, and another for relay 9from battery, upper Winding of relay IIO, contacts of relay I02,resistance I01, contacts of the ringing key I08, ring conductor,contacts of relay I03, contacts of relay I0, lower right-hand winding ofrepeating coil 6, winding of relay 9, contacts of relay I to ground.Relay I in operating closes an obvious circuit for relay 8, and relay 9in operating closes an obvious circuit for relay I2. Relay 8 inoperating closes a holding circuit for relay 3 and a circuit for theoperation of the stepping magnet I3 from battery, winding of this magnetand its self-interrupting contacts, contacts of relay I4, brush andfirst contact of bank B, upper inner armature and front contact of relay8 to ground. This causes the stepping magnet to take one step and isthen operated repeatedly from the ground on the succeeding contacts ofits bank B of other subscribers lines until the terminal of the line Iis reached where the ground has been removed by the line relay 2. Thestepping magnet then stops operating for a moment to mark the callingline connection on this bank. Relay 2 is now fully operated from batterythrough the Winding of stepping magnet I3, its self-interruptingcontacts, contacts of relay I4, brush of bank B, the marked contact, thelower inner armature and front contact of relay 2 and the lower windingto ground. The stepping magnet I3 does not operate in this circuit. Theoperation of relay 2 closes a circuit for the operation of relay I4 frombattery, winding of this relay, contacts of relay 8, contacts of relay 2to ground. Relay I4 in operating closes another circuit for steppingmagnet I3 from battery, winding of this magnet and its self-interruptingcontacts, second lower armature and front contact of relay I4, contactsof bank A and its brush to ground at whatever contact the brush of thisbank is located. As the stepping magnet now operates, it moves the brushof bank A to the next contact, where the stepping magnet is againoperated. This repeated operation of the stepping magnet is continueduntil the brush reaches the eleventh position on bank A where no groundis found for the stepping magnet which then stops. The callingsubscribers tip and ring conductors are connected to the eleventhposition of banks D and E and the brushes of these banks thereforeconnect the tip and ring conductors, over contacts of relays 4, and I2through the left-hand windings of repeating coil 6. A connection isalready completed through the right-hand windings of repeating coil 6 atthe fourth lower armature and front contact of relay I2 for the tip andring conductors overv the trunk so that a talking circuit is therebyprepared between the calling subscriber and the operator at the mainoilice. It should be noted that there are two circuits for the windingsof relay IIO, one extending from battery, upper winding of this relay,upper outer armature and front. contact of relay I02, resistance I 01,contacts of ringing key I08, the ring conductor of the trunk, contactsof relays 3 and I0, lower righthand winding of repeating coil 6, windingof relay 9 to the ground at relay I, while the other extends frombattery, springs of jack I04, lower winding of relay IIO, contacts ofrelay I02, the tip conductors of the trunk, contacts of relay 3, upperright-hand winding of repeating coil 6, winding of relay I to ground atrelay 3. These circuits are in opposite directions through the windingsof relay I I0 so that this relay does not operate at this time.

When the operator finds that the desired subscribers line is a localsubscriber in the branch exchange, that is, one connected in the samemanner as subscriber I, she will connect her dial III through plug H2 injack I04. While this opens the connection through the lower winding ofrelay IIO from the battery at the springs of jack I04, the connectionfor this winding is extended through the springs of jack I04, plug I I2;and pulsing contacts of dial III to battery sothat relay IIO will remainreleased. When now the operator actuates the dial I I I, a pulsingcircuit is completed over the tip conductor for the pulsing relay I, theoriginal circuit being extended from battery pulsing contacts andoperated on normal contacts of the dial sleeve terminals of plug H2 andjack I 04, contacts of relay I02, tip

I conductor, contacts of relay 3, outer right-hand upper winding ofrepeating coil 6, winding of relay I to ground at contacts of relay 3.When the dial returns to normal, the pulsing contacts cause relay I torelease for each impulse. On each release of relay I a circuit iscompleted for the stepping magnet I3 from battery, winding of thismagnet, contacts of relay I4, lower armature and back contact of relayI. Relay 4 is also operated in this circuit and remains operated duringpulsing. Stepping magnet I3 steps the brushes of switch SS to theterminals of the called line such as for example, if the subscriber at Iwas the called party, the brushes would step to the terminals to whichthis line is connected with its tip and ring conductors in banks D andE.

On completion of dialing the operator rings the called subscriber byoperating the dialing key I08. This opens the tip and ring sides of thetrunk and impresses ringing signals from the generator H3 on the ringside of the trunk connection. Relay H0 is prevented from operatingduring the ringing as a circuit is completed for the upper winding,contacts of relay I02, contacts of ringing key I08, through a resistanceto ground. When the operator operated the ringing key, the connectionfor the ring side was only momentarily opened and this permitted therelease of relay 9. Relay 9 in releasing causes the release of relay I2which closes a circuit to the called subscriber at the inner lowerarmature and back contact over the ring conductor for the ringingcurrent from the generator II 3 through contacts of relays 4 and I0 andbrushes of banks D and E, back over the tip conductor, the upper innerarmature and back contact of relay I2 to ground at the contacts of relayI4.

Ringing current from generator I I3 also passes through the right-handlower winding of repeating coil 6, winding of relay 9 to ground at thecontacts of relay I. Relay 9 does not operate under these circumstancessufliciently long to reoperate relay I2, as relay I2 is slow inoperating. Ring back tone is afforded the calling subscriber through thecondenser I6. When the called subscriber answers, and the operatorreleases her ringing key a talking connection is again established fromthe calling subscribers line to the called subscribers line as relays 9and I2 are again operated.

When either party rings ofi by means 01' a hand generator, relay I09operatesin. the trunk circuit over the tip. and ring conductors andlocks up over its upper winding to ground at the closed contacts of jackwe; Relay I09 closes a circuit for the disconnect lamp H4 and theoperator removes her'plug I05 from jack 196, thus releasing relays Hi9and E92. Relay 02 in releasing removes the windings of relay H fromacross the trunk, opens the tip connection and closes a circuit fromthe'charging battery IBI through the windings of relay Hill to the ringconnection of the trunk. Relay 1 releases, causing the release of relays8 and I 4. Relay l4 closes'a stepping circuit from ground. over thewipers of brush or bank A, contacts of relay l4, self-interruptingcontacts and winding of the stepping magnet I3 to battery. Relay 4' isalso operated in thiscircuit, the stepping magnet now returns the switchSS to normal and when the brush of bank A leaves the last contact, thestepping circuit is broken and the switch comes to rest in the homeposition. The remaining relays 3, 2 and 4 are released and charging isresumed over both sides of the trunk current passing through the windingof relay 5 which reoperates. Relay 2 will not reoperate even though thecalling subscriber has the receiver oif the hook as this relay can onlybe originally operated through current produced by the hand generator atthe calling subscribers set.

In making calls from the branch exchange to a subscriber in the mainexchange the operation of the system is the same as described heretoforeup to the point where the operator answers the call after which theoperator extends the connection to the desired subscriber in anywellknown manner.

In making calls from the main exchange to a subscriber in the branchexchange the operator inserts plugs I05 into jack I06 thereby causingthe operation of relay Hi2. This relay causes the release of relays IE0and 5. Relay 5 in releasing closes a circuit for the operation of relay3. This relay in operating closes the tip and ring of the trunk throughto the repeating coil 6 to complete the operating circuit for relays-1'and 9 and the circuits function as described for a call originated by abranch exchange subscriber except that as no line relay is operated allmarking contacts on the bank 2 will be grounded and the switch willrotate directly to the talking position on contact H and from then onrespond to impulses from the operators dial as heretofore described toestablish a connection to a desired called subscribers line. Thissubscriber will then be rung in the usual manner.

If the trunk is in use and another branch exchange subscriber shouldcall, the line relay of this subscribers line will operate and lock upin the first step position in the usual manner but as the relay l2 willbe operated due to the previous connection a circuit will be establishedfrom ground at the third upper armature and back contact and secondupper armature and front contact of this calling subscribers line relay,the second lower armature and back contact of relay 4, second lowerarmature and front contact of relay I2, upper armature and back contactof relay 9, which at this time will be operated only to its firstposition, to battery through the winding of relay 2!), and also throughthe lower armature and. back contact of relay I0 through the winding ofrelay 2| to battery. Relays 2D and 2! will now operate. Relay 2!] inoperating closes a circuit for the operation of relay 22 from battery'through one-half of the repeating coil 23,

lower winding of relay 22, lower armature and. front contact of relay20, the other winding of retardation coil 23 to ground. Relay 22operates and closes a parallel circuit'for its upper winding armatureand front contact and as these two windings are opposed a buzzer actionis set up and a tone is generated which is applied to the line throughthe upper armature and front contacts of relay 2%, resistance 24 and thelower right-hand winding of the repeating coil 5. This tone will beaudible to the operator and to the subscribers talking on theestablished connection. Relay 2! which may be of the vibrating typecloses a circuit for operating relay In. Relay lil in operating opensthe ring side of the trunk at its upper armature and back contact andmaintains a holding circuit for relay l2 so that this relay will notrelease when the trunk is opened. Relay ii! also opens a circuit forrelay Zi which releases slowly. Relay 2! again closes a circuit forrelay l6 and this cycle is repeated. ,The opening and closing of thering side of the trunk causes the alternate operation and release ofrelay H39 in the trunk which thus causes the line lamp M4 to flash toindicate to the operator that a second party is waiting to make a call.Condenser 25 bridged across the onnections through the upper armatureand back contact of relay [0 of the ring side of the trunk affords aby-pass for the tone while these contacts are open. The operator at themain office may remove the tone and stop the flashing by operating atone and flash key IIB which short-circuits the resistance it? and thusallow relay 9 tooperate to its second step position and. open theoperating circuit for reiays 26 and 2| causing them to restore. When theparties talking over the established connection ring off the operatorwithdraws her plug momentarily allowing the circuits to release aspreviously described and then plugs in again whereupon the switch SSwill at once hunt for the waiting line. The circuits then function asbefore to establish a connection from this other calling subscriber tothe operator at the main ofiiee and to establish a connection to anothersubscriber at the branch exchange or to extend the connection tosubscribers at the main exchange as desired.

What is claimed is:

1. In a telephone system, subscribers lines, a trunk, an automaticswitch, means for connecting a calling subscribers line through saidswitch to said trunk, means for connecting said calling subscribers linedirectly to said trunk independently of said switch connection and meansfor opening said switch connection and connecting a called subscribersline through said switch to said trunk.

2. In a telephone system, subscribers lines, a trunk, an automaticswitch, means for actuating said switch to establish a connectionbetween a calling subscribers line and the trunk and later to establisha connection between a called subscribers line and the trunk and meansfor establishing a connection between the calling subscribers line andthe trunk independent of said switch and prior to the actuation of saidswitch for the establishing of the connections between the calledsubscribers line and the trunk.

3. In a telephone system, subscribers lines, a trunk, an automaticswitch, means responsive to a signal from a calling subscribers line forconnecting said line through said switch to said trunk, means responsiveto a signal over said.

trunk for connecting said calling subscriber's line directly to thetrunk independent of the switch connection, and means responsive todialing impulses received over said trunk for actuating said switch toopen the connection therethrough for the calling line and to establish aconnection to a called subscribers line from the trunk.

4. In a telephone system, subscribers lines, a trunk, an automaticswitch, means for establishing a connection from a calling line directlyto said trunk and between a called line and said trunk through saidswitch'operative through the actuation of said switch once as a finderand. the second time asa connector.

5. In a telephone system, an exchange, an operators position, a signalat the operators position, subscribers lines terminating in saidexchange, a trunk line terminating at one end in said exchange and atthe other end in said operators position, a switch in said exchange,means responsive to a ringing signal from a calling subscriberstelephone for establishing a connection through said switch to saidtrunk and to actuate the signal at the operators position, meansresponsive to the operator answering a call for disabling the signal andconnecting the calling subscribers line to said trunk independent ofsaid switch and means responsive to dialing impulses from said operatorsposition received over said trunk for actuating said switch toconnect acalled subscribers line to said trunk, means thereafter responsive to aringing signal from another calling subscribers telephone for generatinga ringing signal that is audible over the connection already establishedbetween a calling subscriber, a called subscriber and the operator.

6. In a telephone system, subscribers lines, a trunk, an automaticswitch, a line relay for each subscribers line, means responsive toringing signals from a calling subscribers telephone for partiallyoperating the line relay of said calling subscribers line, for actuatingsaid switch to a position identifying the calling subscribers line andfor thereafter fully operating said line relay, means responsive to thefull operation of said line relay for further actuating said switch toconnect the calling subscribers line through contacts of said switch andthrough contacts of said relay to said trunk, means responsive to asignal incoming over said trunk for connecting said calling subscribersline to said trunk independent of the connection through contacts of theswitch.

7. In a telephone system, subscribers lines, a trunk, an automaticswitch, a line relay for each subscribers line, means responsive toringing signals from a calling subscribers telephone for partiallyoperating the line relay of said calling sub scribers line, foractuating said switch to a position identifying the calling subscribersline and. for thereafter fully operating said line relay, meansresponsive to the full operation of said line relay for furtheractuating said switch to connect the calling subscribers line throughcontacts of said switch and through contacts of said relay to saidtrunk, means responsive to a signal incoming over said trunk forconnecting said calling line to said trunk indepndent of the connectionthrough contacts of the switch, and means responsive to dial pulsesincoming over said trunk for operating said switch still further toconnect said trunk through contacts of the switch to a correspondingcalled subscriber's line.

8. In a telephone system, subscribers lines, a

trunk, an automatic switch, and means eflective through the operation ofsaid switch in two independently and successively controlled movementsfor establishing a connection from a calling line directly to said trunkand between the trunk and a called line through contacts of said switch.

9. In a telephone system, subscribers lines, a trunk, an automaticswitch, a line relay for each subscribers line, and means forestablishing a connection between two subscribers lines with the trunkas a link and with a calling line connected to the trunk only throughcontacts of the line relay of said calling line and the called lineconnected to the trunk through contacts of the switch.

10. In a telephone system, a branch exchange, a main exchange, anoperators position at the main exchange, an automatic switch in saidbranch exchange, a trunk with one end terminating in said switch at thebranch exchange and terminating at the other end at said operatorsposition at the main exchange, subscribers lines in said branch exchangeterminating at two points in said switch, means responsive to a callingsubscriber transmitting a ringing signal over his line for operatingsaid switch, to connect said calling line to said trunk at one of saidterminating points, means responsive when the operator seizes the trunkat the main exchange in answer to the connection of said trunk to a.calling subscribers line for connecting the calling subscribers linedirectly to the trunk independent of the connection at the switch, andmeans thereafter responsive to signal impulses transmitted from theoperators position in the main exchange over the trunk for furtheroperating said switch to connect a called subscribers line to the trunkat the other terminal point.

JOHN C. KELLY.

